Fix wasm build

Author: youknowone

Cargo.toml

@@ -22,8 +22,10 @@ _bigint = ["dep:num-traits", "dep:num-integer"]  # Internal feature. User must u
 # See also: https://github.com/python/cpython/issues/132763
 mul_add = []
 
-[dependencies]
+[target.'cfg(any(unix, windows))'.dependencies]
 libc = "0.2"
+
+[dependencies]
 num-complex = { version = "0.4", optional = true }
 num-bigint = { version = "0.4", optional = true }
 num-traits = { version = "0.2", optional = true }